Artificial leg



C. B. WINN.

ARTIFICIAL LEG.

APPLlcmoN FILED MAR, 12. 1920.

Patented May l24, 1921.

UNTED STATES PATENT OFFQE.

ARTIFICIAL LEG.

Specication of Letters Patent.

Patented May 24, 1921.

Application led March 12, 1920. Serial No. 365,202.

To all io/wm t may concern Be it known that I, CHESTER B. WINN, acitizen of the United States, residing at Buffalo, in the county of Erieand State of New York, have invented new and useful Improvements inArtificial Legs, of which the following is a specification.

This invention relates to the devices employed in artificial legs forcushioning the forward and backward movements of the jointed leg andfoot members. y

One of the objects of the invention is to so construct the leg that oneand the same part performs the double function of an elastic heel andaspring ,for returning the foot to its normal position, thus simplifyingthe leg and reducing its cost.

A further object is the improvement of the spring or cushion on thefront side of the ankle joint or journal with a view to relieving itfrom undue wear and stress and lengthening its life, as well as'preventing breakage of the cushion and the foot.

In the accompanying drawings:

Figure 1 is a side elevation of an artificial leg embodying theinvention showing the parts in their normal position. Fig. 2 is asectional elevation showing the parts in the same position by fulllines. Fig. 3 is a sectional elevation showing the leg-members tiltedforward and the foot in a level position. TEig. et is a cross section online 4--4, Fie. 2.

Similar characters of reference indicate corresponding parts throughoutthe several views.

10 indicates the foot, and 11 the leg member or shin section, whichparts are jointed together by an ankle journal of any suitableconstruction. In the example shown, this journal comprises the usualtransverse sleeve 12 seated in a concave cavity in the upper rearportion of the foot, and a pin 13 passing through the sleeve, the latterbeing secured to the leg member by a bolt 14 and the pin being fastenedto the foot member by a bolt 15. In its bottom and its rear side thissleeve has the usual transverse slot 16 for the passage of the lowerbolt 15.

Arranged on the front side of the anklejournal and interposed betweenthe front portion of the leg member and the opposing inclined face 17 ofthe foot is the customary stop or cushion 17a of leather or otherappropriate material which limits the forward movement of the leg memberand the upward movement of the foot. This stopcushion may be nailed orotherwise yfastened to the foot, and the adjacent portion of the legmember may be socketed as usual to receive said cushion.

Applied to the rear portion of the foot is a block 18 of soft rubber or`other suitable material constructed to form a combined elastic heel anda spring for returning the foot to its normal position when the legmember is tilted backwardV on the anklejournal. For this purpose,the'upper portion 19 of said heel block extends well up into the base ofthe leg member which is preferably provided with a socket 2O for itsreception. This block is glued or otherwise secured to the reary end ofthe foot, but is detached from the leg-member. In its preferredconstruction the block extends forwardly to the ankle-journal, as shown.

The upper portion of the foot is provided just in front of said journalwith a socket or cavity 21 having an enlarged bottom portion 22 which isoccupied by a spring cushion or 'spring-preferably in the form of asoft-rubber ball 24;. In the upper portion of said socket, which ispreferably cylindrical, slides a plunger 25 of a hard, durable material,such as wood or metal, which is interposed between said ball and theinclined front face `26 of the leg member, so as to move forward withthe leg member and compress the spring ball, causing the latter by itsreaction to return the foot to its normal position. The plunger is ofthe proper length for this purpose, and passes through an opening 27 inthe stop cushion l a. Very satisfactory results have been obtained bydisposing the plunger and its socket at an angle of about forty-fivedegrees, as shown, but I do not wish to be limited to that particulararrangement, as the same may be varied more or less without sacrificingthe advantages of the improvement.

The toe portion 28 of the foot is preferably jointed thereto by theusual strip 29. but it may obviously be rigid and integral with the mainpart of the foot, if desired.

In the use of the artificial leg when the weight of the wearer is placedthereon, the spring rubber heel-block 18 is compressed, largelyrelieving the jar that usually accompanies this movement 'in artificiallegs of ordinary construction, lVhen the leg member is tilted backward,as shown by dotted lines in Fig. 2, said rubber block again comes intoplay, being compressed and by `Yits recoil returning the foot to itsnormal position.

This rubber block thus serves not only as av spring heel, but also as areturn-spring for,

the foot. By thus combining: these two functions in a unitary member,the construc- `forward action of the leg is received by theplungerinstead of the rubber ball or equivalent cushion, the life ofthis Jliront cushion is considerably lengthened, and a material savingin repairs is effected. Atl the same time, crushing or excessive`pressure on this front cushion is prevented by the limiting cushion 17 awhich serves asa protecting stop for the ball, thus further increasingits durability. y

It will be understood from the foregoing that one of the importantfeatures of my invention consists in so constructing and arranging theparts that the rubber ball or equivalent member acts only. as a returnspring for the foot, and not as a combined front stop for the leg-memberand a return spring for the foot, that stop function being performed bythe separate and less elastic limiting cushion 17, thus relieving theballspring 17 from the otherwise excessive pressure which soon impairsits elasticity and in leg member is tilted forward Y block and the baseof the leg-section, as well as the liront stop cushion 17 and the leg-.y section i'ace- 26, to be shaped lor shimmed to obtain thedesiredadjustment or range of motion or' the leg and toot membersrelatively to each other to closely imitate the action or' the naturalleg and foot in walking.

Ehe construction herein shown and described also dispenses with separatedevices such as cords orv tendons, for checking the articulatingmovements of the parts.

l claim as my invention: y

1. rin artificial leg, comprising a leg-member, a toot jointed thereto,and an elastic block secured to the rear end of the foot and Aextendingupwardly against the base of the leg-member, said block being detachedfrom said leg-member and forming a combined heel and return-spring forthe foot.

2. An articial leg, comprising a leg-meinH ber, a foot jointed theretoby an ankle-jeun nal, the Atoot being provided in Vrront of said journalwith a socket, a cushion seated in said socket, land a rigid plungerguided in lsaid socket and interposed between said cushion and the loweriront portion 4oit the leg-member.

onnsfrnn B. wiNN.

